14A-41 |
Processing acid whey for its incorporation in to probiotic yogurt |
G. G. SINGHAL1, R. M. Parmar1, R. I. Dave1, and C. Ren2. (1) MN-SD Dairy Foods Research Ctr., South Dakota State Univ., Dairy Science Dept., Box 2104, Brookings, SD 57006, (2) Plant Science Dept., South Dakota State Univ., 204 Agricultural Hall, Box 2207-A, Brookings, SD 57007 Cottage cheese whey (CCW) could be a good source of pre-digested nitrogen for yogurt and probiotic bacteria. The objective was to optimize the incorporation of CCW solids and make it a functional yogurt ingredient. CCW and ultra filtered CCW were used to replace 1.9%, 5.5% and 11.1% of the total milk protein (4.5%) in yogurts manufactured using long set (ABT-1) and short set (ABT-4) starter culture. Yogurts were analyzed for pH, titratable acidity and viable counts (yogurt and probiotic) during manufacture and during storage on 10, 20 , 30 and 40 days. Yogurt samples were also analyzed for syneresis, gel strength and viscosity on day 1. Sensory evaluation was performed by a panel of 5 expert judges. ABT-1 had a curd set time of 8 h at 11.1% and 10 h at 5.5% CCW supplementation compared to 12 h for control and 1.9% CCW supplementation. No difference in curd set time was observed for ABT-4 starter culture. Syneresis was lower with ABT-1 culture compared to ABT-4 (p<0.05). For ABT-1 starter culture, syneresis was lowest at 11.1% CCW supplementation. At 11.1% level of supplementation, yogurts from ABT-1 also had firmer gel as measured by cone penetration (p<0.05) but no difference was observed in gel strength at 1.9% and 5.5% CCW supplementation. Also, there were no differences in viscosity of control and 1.9% CCW supplemented yogurts for both the starter cultures. Yogurts made with CCW supplementation were equally (p>0.05) acceptable as control yogurt. Viability of Lactobacillus acidophilus was one log cycle higher for upto 30 d storage in yogurts made with ABT-4 and 5.5% and 11.1% CCW supplementation. Thus, we can use CCW to replace upto 11.1% of total milk protein without adversely affecting yogurt quality and increasing the viability of probiotic bacteria.
Session 14A, Dairy Foods: General developments in dairy technology I
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